目的 探讨原发性胃癌（PGC）患者术后体质指数（BMI）与预后的关系。方法 选取巴中市中心医院2011年1月至2016年12 月收治的362例PGC患者作为研究对象，根据BMI中国标准分为低体重（BMI<18.5 kg/m2 ）、正常体重（BMI 18.5~23.9 kg/m2 ）、超重（BMI 24.0~27.9 kg/m2 ）、肥胖（BMI≥28.0 kg/m2）四组，采用Kaplan⁃Meier法计算生存期和无病生存期，4组间的差异比较采用Log⁃rank检验， 采用Cox比例风险模型进行预后影响因素分析。结果 低体重、正常体重、超重和肥胖的PGC的3年无病生存率分别为：90.0%、77.4%、 78.9%和79.8%，经Log⁃rank检验，组间差异无统计学意义（χ2=1.110, P=0.832）；低体重、正常体重、超重和肥胖的PGC的5年总生存率 分别为：32.3%、86.9%、71.5%和69.0%，经Log⁃rank检验，组间差异有统计学意义（χ2=7.616, P=0.027），且进一步两两比较发现，低体 重和肥胖患者的总生存率水平最低。多因素分析显示，相对于正常体重患者，肥胖（BMI≥28.0 kg/m2）患者（RR=1.559，95%CI= 1.262~ 2.420, P=0.022）、体重过低（BMI≤18.5 kg/m2）患者（RR=3.385，95%CI=1.698~6.767, P=0.002）是影响PGC患者术后生存的独立危险 因素。结论 术后体重过低及肥胖可作为影响原发性胃癌生存率的独立影响因素。

Objective To investigate the relationship between postoperative body mass index(BMI) and prognosis in patients with primary gastric cancer(PGC). Methods 362 cases of PGC in Bazhong Central Hospital from January 2011 to December 2016 were selected as the research objects. According to the Chinese standard of BMI, they were divided into low weight (BMI<18.5 kg/m2) , normal weight(BMI:18.5-23.9 kg/m2 ), over weight(BMI:24.0-27.9 kg/m2) and obesity(BMI≥28.0 kg/m2 ). Kaplan⁃Meier method was used to calculate OS and DFS in 4 groups , Log rank test was used to compare the differences among the 4 groups. Cox proportional hazard model was used to evaluate the prognosis factor analysis. Results The 3⁃year DFS of PGC with low weight, normal weight, overweight and obesity were 90.0%, 77.4%, 78.9% and 79.8%, respectively. By Log⁃rank test, there was significant difference between the groups (χ2= 1.110, P=0.832); the 5⁃year OS of low weight, normal weight, overweight and obese PGC were 32.3%, 86.9%, 71.5% and 69.0%, respectively, and the difference was statistically significant (χ2=7.616, P=0.027), and further pairwise comparison found that the OS level of low weight and obesity patients was the lowest. Multivariate analysis showed that obesity (BMI≥28.0 kg/m2) patients (RR=1.559, 95%CI= 1.262-2.420, P=0.022) and underweight (BMI≤18.5 kg/m2) patients (RR=3.385, 95%CI=1.698-6.767, P=0.002) were independent risk factors for postoperative survival of patients with PGC. Conclusion Postoperative underweight and obesity can be considered as independent factors affecting the survival rate of primary gastric cancer.